This paper presents a study on interior permanent magnet synchronous motors (IPMSM) design with different PM materials, ferrite and NdFeB magnet, for achieving high efficiency performance. The high efficiency performance for IPMSM is analyzed based on energy losses balance analysis between iron losses, copper loss and mechanical loss. In addition, the important machine characteristics are also analyzed. The finite element analysis (FEA) is used to precisely calculate machine parameters, and then the equivalent circuit method (ECM) is performed for predicting motor performances. The calculated results are confirmed by testing the two type Ferrite/NdFeB IPM synchronous motors. In final, the high-efficiency IPMSM design process is concluded.